This invention relates to a surveillance device and, in particular, to a surveillance device which employs a camera and lens assembly.
A type of surveillance device is known in the art in which a camera and lens assembly is utilized in the surveillance device to permit the device to view the location being placed under surveillance. The surveillance device is provided with a housing for housing the camera and lens assembly. A typical housing includes an upper support section which may be dome-shaped and from which the camera and lens assembly is suspended. A lower section, which may also be domed-shaped, abuts the upper section to complete the housing and fully enclose the camera and lens assembly. The lower section is also light transmissive to permit viewing by the camera and lens assembly outward of the housing.
In the above-type of surveillance device, the lens and camera assembly is carried by a mounting member which is coupled to the support section of the housing so as to be rotational about a first axis, usually a vertical axis. The lens and camera assembly is furthermore supported on the mounting member such that the assembly itself is rotatable about a second axis, usually a horizontal axis. In this way, by rotation of the mounting member and rotation of the camera and lens assembly, the latter can be moved in a horizontal plane and a vertical plane, respectively, to provide the so-called "panning" and "tilting" motion of the assembly. This, in turn, provides the desired viewing coverage of the location under surveillance.
Also employed in some surveillance devices of this type is an opaque or non-light-transmissive enclosure or shroud. This shroud is affixed to and rotates with the mounting member and extends between the lower housing section and the camera and lens assembly. The shroud thus shields the camera and lens assembly, making the assembly difficult to observe through the light-transmissive housing section. This prevents a subject under surveillance from readily removing himself or herself from the camera field of view.
The above use of a shroud in a surveillance device requires that the shroud be provided with an elongated, vertical slot. This slot permits the camera and lens assembly to view outward of the shroud over the extent of the tilting motion of the assembly. However, the presence of the slot also permits viewing of the camera and lens assembly through the slot from certain viewing angles. This detracts from the desired shielding function of the shroud.
In U.S. Pat. No. 4,833,534, assigned to the same assignee hereof, an additional non-light-transmissive shutter is provided in the surveillance device to mitigate against the undesired effects of the slot. This shutter is arranged to move with the tilting motion of the camera and lens assembly so as to fill or occupy the region of the slot not blocked by the assembly itself. While the presence of the shutter substantially prevents viewing of the camera and lens assembly through the slot, it also requires the use of an additional moving part and the coordinating of the movement of this part with the tilting movement of the camera and lens assembly.
In the above-type surveillance device, it has also been customary to bolt the mounting member carrying the camera and lens assembly to the upper support section of the housing. This has made installation and servicing of the camera and lens assembly time consuming and difficult, particularly in overhead or ceiling installations. Accordingly, designs are being sought for the mounting member which enable the member to be installed and removed more quickly and with less effort. One such design is disclosed in U.S. Pat. No. 4,945,367, in which the mounting member is provided with slots which are received by depending pins situated in the support section of the housing. By twisting the mounting member, the slots become locked to the pins so that the desired connection of the mounting member to the support housing is realized.
The above arrangement of the '367 patent, however, still requires alignment of several slots in the mounting member with corresponding pins in the support housing. This alignment procedure can be a difficult process, particularly when the weight of the camera and lens assembly is considered and the installation is overhead.
In the above-type surveillance devices, the camera and lens assembly usually comprises a camera/lens mounting for coupling the lens of the assembly to the camera image pick-up unit of the assembly. The image pick-up unit may or may not have attached to it the remainder of the camera body, depending upon certain length requirements of the surveillance device.
In a typical camera/lens mounting, the mounting is adapted to engage a cylindrical collar at the back end of the lens. This collar has an annular slot which receives a first wider cylindrical end of a shouldered member, referred to as a "C-mount", which forms a part of the camera/lens mounting A narrower second cylindrical end of the shouldered C-mount is then adapted via a threaded section to receive the threaded front end of the image pick-up unit.
In order to hold the C-mount in place, the camera/lens mounting is further provided with a locking ring or nut. This nut has an inner surface which bears against the shoulder of the C-mount as the ring is locked to the collar via internal threads which mate with external threads on the collar.
In the above camera and lens assembly, once the pick-up unit is locked to the lens via the camera/lens mounting, it may be necessary to adjust the position of the image pickup relative to focal point of the lens. This is presently accomplished by an adjusting mechanism included in the image pick-up unit which allows preselected movement of the components of the unit. This adjusting mechanism is often of complicated mechanical design and, therefore, other techniques for making this so-called "back-focus" adjustment are being sought.
It is, therefore, an object of the present invention to provide a surveillance device in which the security of the device is better preserved.
It is a further object of the present invention to provide a surveillance device in which enhanced shielding of the camera and lens assembly of the surveillance device is realized.
It is also an object of the present invention to provide a surveillance device in which the installation and removal of the camera and lens assembly is made easier and quicker.
It is yet a further object of the present invention to provide a camera/lens mounting for the camera and lens assembly of a surveillance device which allows for easier adjustment of the camera image pick-up unit relative to the lens of the assembly.